Consitpation in raw fed cat

I recently transitioned all three of my cats to raw fed. I am buying a pre-made from Balanced Blends. I think it may be bone heavy because one of my cats is not defecating much. It's going on four days and I am concerned. My other two are going about every two-three days. I've begun to add more meat and organ to the pre-made in hopes to bring down the bone percentage. At any rate, I know they defecate less when on raw, but at what point should I be concerned? My cat is 8 months old, he's still full of energy and happy...just not pooping! Any advise?

Can you add more fat to the raw? That helps with constipation. Animal fat/skin works really well and is easy to find. 

Are you sure that cat hasn't defecated, and that all the poop you've seen if from your other two cats?  Is he going to the litter box and straining/crying?

Raw fed cats don't poop much.  My 15 lb monsters produce maybe 2-3 small (like 1-2") poop pieces a day and will often go 2-3 days without pooping.  This sounds like a big, sudden change for your cats though.  Try adding a bit of canned pumpkin to their food to make sure they're transitioning ok, if you notice signs of straining in the litter box.

My youngest cat was constipated on her old food, it was quite obvious. She ended up vomiting, and obviously in pain. After an expensive vet visit, with xrays, she was put on a laxative for awhile. Since switching to raw I am careful to keep the bone content at 7%, rather than 10% as often recommended. No issues. All my kitties use the litter box regularly with no issues. But there is a lot less poop than there was before I switched to raw. I'd suggest a vet visit if you are truly concerned, but if the cat is in good spirits and doesn't seem in distress it is likely ok.